I wrote [“We Don’t Talk Anymore”] in Japan, I was in my hotel room, at the Mandarin Hotel, looking out at this wonderful city from the top floor, and I called my guitarist who was in the next room and I said, ’Dude, can you come to my room really quickly and play this guitar line?’ I didn’t have a microphone, so I recorded his guitar with my iPhone, and I put it in the mix. Then, we went to the Philippines the next day, and I put the kick drum in.

What have the artists said about the song?

I was driving on Santa Monica Boulevard with my friend, and I hadn’t seen him in like four months, and last time I saw him he was so infatuated and in love with this girl, and would literally talk about her every second, and always just literally with the ups and downs and the sideways and whatever. When I saw him after four months of not seeing him, of being on tour, I was like, ‘Oh, how is so-and-so doing?’ And he was like, ‘Oh, we don’t talk anymore.’ And literally as he said that I was like, ‘We don’t talk anymore. We don’t talk anymore. We don’t talk anymore. Like we used to do.’ Simple. And that’s the dude that came into the ‘Marvin Gaye’ session when I was writing ‘Marvin Gaye’ too, so he has has a nice, strong energy about him.

How did Selena and Charlie come together to make the song?

Taylor Swift introduced us at this VMA afterparty a while back. I think I even was like, “We should do something sometime.” But I didn’t actually think it was gonna happen.

I think four months went by, and it happened – but in a very strange way. I had sent the demo of “We Don’t Talk Anymore,” where it was originally all me, and I played it for her over FaceTime. She was like, “I love this,” and it hit me. I was like, “This could be a duet.”

Selena was in Vegas. She flew herself to my house I was renting at the time in the Hollywood Hills. She came over at like 2 o’clock in the morning and recorded this part in a makeshift recording booth in the closet. It was very, very not glamorous. I had to go to London the next day – I was kind of hungover, I just came from a party. But I had to get the vocals all done. So it was quite challenging to just push through it at 5 o’clock in the morning. But when I listened to it when I woke up the next day, it was all worth it, ‘cause she sounded great.